US10492816B2 - Load sensing resection device - Google Patents

Abstract

Embodiments of the invention include drive units and other effective types of movement inducing devices that include load sensing mechanisms capable of giving feedback to a user when a force is being applied to the devices during use. The applied force for which monitoring is provided may be one or more of a lateral force transverse to a longitudinal rotating axis of a surgical blade, burr, or other mechanism, a force applied along the longitudinal rotating axis, and other forces.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National phase entry of PCT/US2015/043994 filed Aug. 6, 2015 and titled “Load Sensing Resection Device.” PCT/US2015/043994 claims the benefit of U.S. Prov. Pat. Appl. Ser. No. 62/034,991 filed Aug. 8, 2014. Both applications are incorporated by reference herein as if reproduced in full below.

FIELD OF INVENTION

The various embodiments relate to the field of surgical instruments, and more particularly relates to surgical instruments for resecting, cutting, or otherwise manipulating tissue and related methods. Some embodiments include mechanisms capable of sensing loads applied to surgical instruments during use.

BACKGROUND

Surgical cutting or resection devices with drive units and rotating blades or burrs are commonplace in endoscopic surgery. Many current devices include a reusable drive unit and disposable rotating blades, burrs, or other attachments that are configured to couple to the reusable drive unit. During an endoscopic surgery, a surgeon may unknowingly apply forces to an instrument that have the potential of damaging the instrument or causing complications to the surgical procedure when using instruments of the previously existing designs.

It would be advantageous to provide surgical instruments for endoscopic surgery that are capable of monitoring forces applied to the instruments. It may be further advantageous to have the capability to provide alerts of one or more types that notify a user when load limits that have been set for forces applied to the instruments have been reached. Some improved embodiments may include methods of calibrating a cutting tool with integrated force sensors to provide an alert when load limits are reached and methods of calculating loads applied to a cutting tool.

SUMMARY

An embodiment of the invention is a cutting tool that includes a drive unit, a working assembly having a proximal end, a distal end, and a longitudinal axis that passes between the proximal end and the distal end, the working assembly configured to couple with and at least in part be rotated by the drive unit, and two or more sensors positioned between the drive unit and the working assembly. The two or more sensors may be positioned to detect force applied to the working assembly transverse to the longitudinal axis of the working assembly while the working assembly is coupled to the drive unit.

Another embodiment of the invention is a cutting tool that includes a drive unit, a rotatable shaft mounted in a housing and configured to be coupled with the drive unit at a proximal end of the rotatable shaft and be rotated by the drive unit, a cutting element at a distal end of the rotatable shaft, and a plurality of force sensors. The force sensors may be spaced around the housing of the rotatable shaft such that forces applied to the cutting element, rotatable shaft, or the housing transverse to an axis of rotation of the rotatable shaft from any transverse direction are measurable as forces applied to one or more of the force sensors.

Yet another embodiment of the invention is a method of calibrating a cutting tool with integrated force sensors. The method may include providing a drive unit, providing a working assembly having a proximal end, a distal end, and a longitudinal axis that passes between the proximal end and the distal end, the working assembly configured to couple with and at least in part be rotated by the drive unit, and providing sensors configured to measure loads applied to the working assembly. The method may also include the acts of applying a limit load to the working assembly, registering a measured load on one or more of the sensors that results from application of the limit load, and setting an alert to be activated when the measured load registered on one or more sensors is reached.

Still another embodiment of the invention is a method of determining a lateral load on a cutting tool with one or more rotating components. The method may include providing a drive unit, providing a working assembly having a proximal end, a distal end, and a longitudinal axis that passes between the proximal end and the distal end, the working assembly including a shaft configured to at least in part be rotated by the drive unit, and providing two or more sensors positioned between the drive unit and the working assembly at intervals around the longitudinal axis of the working assembly. The method may also include the acts of operating the cutting tool and applying a lateral load to the cutting tool and measuring loads at the two or more sensors while the cutting tool is being operated. If only one sensor measures a significant load while the tool is being operated, then the method may include comparing the measured load to a limit load to determine if an alert should be activated. If more than one sensor measures a significant load while the tool is being operated, then the method may include calculating a resultant load from the loads measured and comparing the resultant load to the limit load to determine if an alert should be activated.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partially exploded perspective view of an embodiment of a cutting tool.

FIG. 2 is a side elevation view of the cutting tool ofFIG. 1.

FIG. 3 is a cross-sectional view of a portion of the cutting tool ofFIG. 1.

FIG. 4 is an additional perspective view of the cutting tool ofFIG. 1.

FIG. 5 is a cross-sectional perspective view of a portion of the cutting tool ofFIG. 1 taken through the section illustrated inFIG. 4.

FIG. 6 is a perspective view of a portion of the cutting tool ofFIG. 1.

FIG. 7 is a cross-sectional view of a distal end of the cutting tool ofFIG. 1 taken through the section illustrated inFIG. 6.

FIG. 8 is a system diagram of an embodiment of a drive unit, sensors, and related equipment.

FIG. 9 is a perspective view of an embodiment of a cutting tool with a partial cut-away section provided to illustrate some internal operation and connectivity of the cutting tool.

FIG. 10 is a partially exploded perspective view with a partial cut-away of the cutting tool ofFIG. 9.

FIG. 11 is a perspective view of a drive unit of the cutting tool ofFIG. 9.

FIG. 12 is a cross-sectional view of a portion of the cutting tool ofFIG. 9 taken through the section illustrated inFIG. 9.

FIG. 13 is a system diagram of the cutting tool ofFIG. 9 in combination with a control system for controlling use of the cutting tool and managing fluids.

FIG. 14 is a cross-sectional view of an embodiment of a cutting tool.

DETAILED DESCRIPTION

Acutting tool100 and its component parts are illustrated inFIGS. 1-7. As used herein the term “cutting tool” may include not only tools that cut with a blade but tools that abrade, scratch, rub, dislodge, or otherwise manipulate tissue. Thecutting tool100 illustrated includes adrive unit101 and aworking assembly150. Thedrive unit101 may be a motorized drive unit powered by an electric motor and a battery, transformer, capacitor, wire, or other source of electricity, may be powered by air pressure or other fluid pressure, may be powered by manual or automated user manipulation, or may be powered by any other effective mechanism. A set ofcontrols105 is illustrated inFIGS. 1, 2, 4, and 5. The set ofcontrols105 may include buttons, switches, sliders, indicators, and other mechanisms or displays to adjust and control functions of thedrive unit101. For example and without limitation, thecontrols105 may be used to one or more of power thedrive unit101 on and off, set a rotating speed for a portion of the drive unit, activate a clockwise or counterclockwise rotation of a portion of the drive unit, indicate a status or function of thedrive unit101, set or express an alert function associated with thecutting tool100 or any of its component parts, and provide any other useful control or display associated with thedrive unit101. Function and control of thedrive unit101 in combination with the other components of thecutting tool100 will be described in greater detail in association withFIG. 8 below. Function and control may also be accomplished by use of a control system coupled with thedrive unit101, and may further include use of separate controls such as foot operated controls.

Theworking assembly150 illustrated inFIGS. 1-4, 6, and 7 includes a proximal end151 adistal end152 and the longitudinal axis that passes between theproximal end151 and thedistal end152. Theworking assembly150 shown is configured to couple with thedrive unit101 and at least in part be rotated by thedrive unit101. As is most clearly shown inFIG. 3, theworking assembly150 may include ahousing170. Thehousing170 may include acannular shaft175 extending toward the distal end of theworking assembly150. Arotatable shaft160 is shown mounted in thehousing170 and therotatable shaft160 in the illustrated embodiment is configured to be coupled with thedrive unit101 at theproximal end151 of theworking assembly150 and therotatable shaft160. Theworking assembly150 and thedrive unit101 are coupled by alignment of guide pins153 (FIGS. 1-4 and 6) and notches103 (FIGS. 1, 4 and 6). Releasable locking of theworking assembly150 with thedrive unit101 is accomplished with alatch154. Insertion of theworking assembly150 into thedrive unit101 leads to engagement of thelatch154 with thedrive unit101. Thelatch154 may be released by pressing theadjacent guide pin153. While pressed, the workingassembly150 may be removed from thedrive unit101. The workingassembly150 includes a torque transfer element155 (FIGS. 1-3 and 6) configured to engage with and be turned by thedrive unit101. Thetorque transfer element155 is coupled with the rotatable shaft160 (FIG. 3) to enable therotatable shaft160 to be turned by thedrive unit101. The workingassembly150 shown also includesseating pads159, as shown inFIGS. 1, 2, 4, and 6, configured to make contact withsensors190 when the workingassembly150 is coupled with thedrive unit101. Theseating pads159 shown are configured to ensure a consistent load transfer between the workingassembly150 and thedrive unit101. In other embodiments, devices such as theseating pads159 may or may not be used to guide load transfer between a working assembly and a drive unit.

A cuttingelement180 is shown inFIGS. 3, 6, and 7 coupled at adistal end162 of therotatable shaft160. In other embodiments, a cutting element may be a module or component configured to couple at a distal end of the shaft by any effective mechanism. Cutting elements may also be integral with a rotatable shaft and may be formed from the same material as a rotatable shaft. Cutting elements of various embodiments may include blades, burrs, rasps, abrasives, or any other devices effective to cut, abrade, scratch, rub, dislodge, or otherwise manipulate tissue.

Sensors190 are shown inFIGS. 4-6 configured to be positioned between thedrive unit101 and the workingassembly150. Thesensors190 depicted are force sensors configured to measure loads applied to the faces of the sensors. In the illustrated embodiment, as best seen inFIG. 5, there are foursensors190 positioned substantially radially equidistantly around the longitudinal axis of the workingassembly150 when the workingassembly150 is coupled with thedrive unit101. In other embodiments, sensors may be positioned at other effective locations within a cutting tool. For example and without limitation, three sensors positioned substantially radially equidistantly around the longitudinal axis of a working assembly when the working assembly is coupled with the drive unit could be used. In the illustrated embodiment, thesensors190 are integral with thedrive unit101. In other embodiments, similar sensors could be integral with a working assembly or could be separate components that are positioned between a drive unit and a working assembly without being integral with either. In the embodiment illustrated, thesensors190 are spaced around the periphery of thehousing170 of therotatable shaft160 when the workingassembly150 is coupled with thedrive unit101. In this configuration, forces that are applied to thecutting element180 within thehousing170 transverse to an axis of rotation of therotatable shaft160 from any transverse direction are measurable as forces applied to one or more of thesensors190. Thesensors190 shown are positioned to detect force applied to the workingassembly150 transverse to the longitudinal axis of the workingassembly150 while the workingassembly150 is coupled to thedrive unit101. Load may further be applied to the workingassembly150 by application of force to any part of thehousing170, including thecannular shaft175, and may be applied through the cuttingelement180 and therotatable shaft160.

Sensors190,290 (FIGS. 9-12),1190 (FIG. 14) may be any effective type of sensor for the applications described herein, including but not limited to, force sensors, pressure sensors, proximity sensors, movement sensors, and other types of tactile sensors. For example and without limitation, sensors may be thin film load cells, devices employing piezoelectric elements, variable capacitance detectors, and strain gauges. Piezoresistive material built on a flexible polyester circuit material with conductive traces may also be used as a sensor with some embodiments. Sensors of various embodiments may be discrete elements physically separate from one another or may include two or more sensors built onto a common structure or backing.

Function and control of thedrive unit101 in combination with the other components of thecutting tool100 are illustrated in a system diagram inFIG. 8.Sensors190 are shown electrically coupled with aprocessor191. An axial sensor1190 (FIG. 14) is also shown electrically coupled with theprocessor191. Theaxial sensor1190 may be present with any of thecutting tools100,200,300 illustrated or with similar cutting tools within the scope of the present disclosure. Theprocessor191 is configured to not only receive and interpret signals from thesensors190,1190, but also to control and display the functions and status of thedrive unit101. Theprocessor191 is coupled with apower control192, which is coupled with arevolution rate selector193 and arevolution direction selector194. Theprocessor191 is also coupled with analert control195 and anindicator196. Thealert control195 may be used to one or both select and indicate whether an alert is to be provided with a lighted indication, an audible indication, a vibratory indication, or any other effective indication. Theindicator196 may be used in association with one or more of the other functions of thedrive unit101. For example and without limitation, theindicator196 may be used to set or display a speed or direction of rotation for the device, may be used as a power indicator, may be used to indicate an acceptable limit load being set for thecutting tool100, or may be used for one or a combination of these or other purposes. Control and display functions may be accomplished with hardwired or so-called “soft” function buttons or keys that are part of thedrive unit101, such as for example, the set ofcontrols105 illustrated. The system may further include display screens of various types. These and other function and control mechanisms may alternatively or in combination be performed by an external control system as more fully described in association withFIG. 13.

Acutting tool200 and its component parts are illustrated inFIGS. 9-12. Thecutting tool200 illustrated includes adrive unit201 and a workingassembly250. A set ofcontrols205 is illustrated inFIGS. 9-12. The set ofcontrols205 may be essentially similar to thecontrols105 described herein. Function and control of thedrive unit201 in combination with the other components of thecutting tool200 may be essentially similar to the descriptions provided herein for thedrive unit101 in association withFIG. 8.

The workingassembly250 illustrated inFIGS. 9, 10, and 12 includes aproximal end251, adistal end252, and a longitudinal axis that passes between theproximal end251 and thedistal end252. The workingassembly250 shown is configured to couple with thedrive unit201 and at least in part be rotated by thedrive unit201. The workingassembly250 may include ahousing270. Thehousing270 may include acannular shaft275 extending toward the distal end of the workingassembly250. Arotatable shaft260 is shown mounted in thehousing270 and in the illustrated embodiment is configured to be coupled with thedrive unit201 at theproximal end251 of the workingassembly250 and therotatable shaft260. The workingassembly250 and thedrive unit201 are coupled by alignment of guide pins253 in notches203 (FIGS. 10-12) and rotation of the workingassembly250 to move the guide pins253 through paths of thenotches203. Releasable locking of the workingassembly250 with thedrive unit201 is accomplished by clockwise rotation while compressing, and unlocking is accomplished by counterclockwise rotation with an initial compression and then separation of the workingassembly250 from thedrive unit201. The workingassembly250 includes a torque transfer element255 (FIGS. 9, 10, and 12) configured to engage with and be turned by thedrive unit201. Thetorque transfer element255 is coupled with the rotatable shaft260 (FIG. 12) to enable therotatable shaft260 and be turned by thedrive unit201. A cutting element essentially similar to thecutting element180 may be coupled at a distal end of therotatable shaft260.

Sensors290 are shown configured to be positioned between (FIGS. 10 and 11) and actually positioned between (FIG. 12) thedrive unit201 and the workingassembly250. Thesensors290 depicted are force sensors configured to measure loads applied to the faces of the sensors. In the illustrated embodiment, there are foursensors290 positioned substantially radially equidistantly around the longitudinal axis of the workingassembly250 when the workingassembly250 is coupled with thedrive unit201. In other embodiments, sensors may be positioned at other effective locations within a cutting tool. For example and without limitation, three sensors positioned substantially radially equidistantly around the longitudinal axis of a working assembly when the working assembly is coupled with the drive unit could be used. In the illustrated embodiment, thesensors290 are integral with thedrive unit201. In other embodiments, similar sensors could be integral with a working assembly or could be separate components that are positioned between a drive unit and a working assembly without being integral with either. In the embodiment illustrated, thesensors290 are spaced around the periphery of aflange259 of thehousing270 when the workingassembly250 is coupled with thedrive unit201. In this configuration, forces that are applied to the cutting element at the distal end of therotatable shaft260 within thehousing270 transverse to an axis of rotation of therotatable shaft260 from any transverse direction are measurable as forces applied to one or more of thesensors290. Thesensors290 shown are positioned to detect force applied to the workingassembly250 transverse to the longitudinal axis of the workingassembly250 while the workingassembly250 is coupled to thedrive unit201. Load may further be applied to the workingassembly250 by application of force to any part of thehousing270 including thecannula shaft275, and may be applied through the cutting element and therotatable shaft260. Thesensors290 may be any effective type of sensor for the applications described herein and may be essentially similar to thesensors190,1190 described above.

Function and control of thedrive unit201 in combination with the other components of thecutting tool200 are essentially similar to the function and control illustrated in the system diagram inFIG. 8.

A control system is illustrated inFIG. 13 coupled with thedrive unit201, which is couple with the workingassembly250, of thecutting tool200. The same or an essentially similar control system may be used with thecutting tools100,300. The control system shown inFIG. 13 includes aresection control510 that is electrically coupled with thedrive unit201 by acable511. Theresection control510 may be used to one or more of provide power to thedrive unit201, receive operator inputs from thedrive unit201, sense operating parameters of thedrive unit201, receive operator inputs from external switches or controls such as foot operated switches or controls, provide, set, or display alerts to a user based on operations of or forces applied to thecutting tool200, and send and receive signals to and from apump control520. Theresection control510 illustrated also includes aresection display panel518, which may be used to communicate information to a user and may be used to input settings or other information into theresection control510 or other connected components of the control system. Other knobs, switches, controls, and the like may be used to control, set, or calibrated theresection control510 as well.

In the illustrated embodiment, thepump control520 is configured to manage fluids used during surgery performed with thecutting tool200. For example and without limitation, fluids such as saline may be used during endoscopic surgical procedures to provide a clear operating medium in which to perform endoscopic surgical tasks. Thepump control520 may be used to one or more of provide fluid to thedrive unit201, sense operating parameters of thedrive unit201, manage waste fluid, receive operator inputs from external switches or controls such as foot operated switches or controls, and send and receive signals to and from theresection control510. Afluid inflow line521 is shown coupled between thepump control520 and a patientjoint cannula522. The patientjoint cannula522 may provide one or both a passageway through which thecutting tool200 may be introduced into a joint and an entry port for fluid supplied though thefluid inflow line521. In other embodiments, one or more additional fluid lines may be used to supply fluid or remove fluid from a surgical site from locations different than those illustrated. Asaline bag523 is shown providing a fresh fluid supply to thepump control520 through asupply line524 in the present embodiment. Asuction line525 is shown coupled between the cuttingtool200 and thepump control520, which when activated draws waste fluid through thecutting tool200 and into thepump control520 where the fluid may be diverted for waste removal. Awaste line527 is shown coupled between thepump control520 and awaste receptacle529. Any other effective supply or waste handling mechanisms may be used in other embodiments. Thepump control520 illustrated also includes a pumpcontrol display panel528, which may be used to communicate information to a user and may be used to input settings or other information into thepump control520 or other connected components of the control system. Other knobs, switches, controls, and the like may be used to control, set, or calibrated thepump control520 as well.

Acutting tool300 and its component parts are illustrated inFIG. 14. Thecutting tool300 illustrated is essentially similar to thecutting tool200, with the addition of theaxial sensor1190. Theaxial sensor1190 shown is placed behind the drive unit's motor to register load applied along the longitudinal axis of thecutting tool300. In other embodiments, an axial sensor could be of any type and could be positioned at any location capable of registering an axial force applied to a working assembly of thecutting tool300. Function and control of thecutting tool300 may be otherwise essentially similar to the descriptions provided herein for thecutting tools100,200.

Another embodiment of the invention is a method of calibrating a cutting tool that has integrated force sensors. For example and without limitation, any of thecutting tool100, thecutting tool200, or thecutting tool300 could be used in such an embodiment. Method embodiments may include providing a drive unit, a working assembly, and two or more sensors as have been described herein in association with thecutting tools100,200,300. Such a method of calibrating a cutting tool may include applying a limit load to the working assembly. A limit load is a load that a designer or user of a cutting tool does not wish to exceed while the cutting tool is being operated. A limit load may be established empirically or through design calculations. An example of an empirical determination of a limit load may include engaging a skilled operator such as a surgeon to apply a load to an operating cutting tool in an amount beyond which, in the surgeon's judgment, operation of the cutting tool should not be continued. Similarly, a load could be applied to an operating cutting tool until it is judged that the cutting tool should not be operated further to avoid damage to the cutting tool. A load limit may be established through design calculations by, for example, calculating a load based on the characteristics of the cutting tool that would create an unacceptable deflection or unacceptable stress in the cutting tool.

With a limit load applied to a cutting tool, the method of calibrating the cutting tool may further include the act of registering a measured load on one or more of thesensors190,290,1190 that results from application of the limit load. In some embodiments, the act of registering a measured load on one or more sensors includes measuring a load on only one of the sensors and not measuring any significant load on any other sensors. As used herein the term “significant load” means a load that is reasonably measurable in light of the loads that are typically applied to a working assembly. For example, in such an embodiment load may have been applied transversely to the longitudinal axis of the working assembly substantially in radial alignment with the only one of thesensors190,290 that measured a load. Consequently, the sensor in a position away from which load is being applied and the sensors with faces transverse to the direction of the applied load would not register a significant load. In other embodiments, the act of registering a measured load may include measuring loads on two or more sensors from which a resultant load is calculated. For example, where a load is applied to a working assembly in a direction between two sensors, some force would be measurable at each of the sensors. Some force may also be measured alone or in combination at an axial sensor such as theaxial sensor1190. A resultant load may be calculated based on the relative magnitudes and directions of the measured loads. Therefore, a measured load to be compared with a limit load may be calculated for a load applied in any particular direction. In still another embodiment, a database of measured loads for all sensors based on applied limit loads may be created by applying a range of limit loads to a cutting instrument and recording a resulting database of measured loads. Such a database of measured loads could be queried as a lookup table in response to operational loadings to determine when limit loads have been reached.

The method of calibrating a cutting tool may further include setting an alert to be activated when the measured load registered on one or more sensors is reached. Various types of alerts may be set. As discussed in describing the system ofFIG. 8, an alert may include visual, audio, vibratory, tactile, or any effective alert mechanism. An alert may also take the form of a degraded, reversed, or halted operation of a drive unit. The act of setting an alert to be activated when the measured load registered on one or more sensors is reached may include setting different measured loads to be reached for different types of working assemblies. Different measured loads may be set for working assemblies of different sizes or different types. For example and without limitation, a greater measured load may be set for a blade with a larger diameter or shorter length than would be set for a blade with a relatively smaller diameter or longer length. Drive units of some embodiments may automatically set a measured load at which an alert will respond. This automatic response may be a result of a working assembly being identified to a drive unit. The identifying act may result from user identification of a working assembly or may result from automatic identification by a drive unit. A non-limiting example of automatic identification and automatic setting of a measured load is a system that includes one or more working assemblies with an arrangement or specific placement of magnets readable by a drive unit. Upon reading of the arrangement of magnets, such a drive unit may automatically set a measured load beyond which an alert will be activated. In other embodiments, a drive unit may automatically set a measured load by identifying a working assembly based on any effective identification mechanism. For example and without limitation, identification may result from reading a radio frequency identification (RFID) code, an optical code, or a mechanical characteristic of a working assembly.

Another method embodiment is a method of determining a lateral load on a cutting tool with one or more rotating components. For example and without limitation, any of thecutting tools100,200,300 could be used in such an embodiment. Method embodiments may include providing a drive unit, a working assembly, and two or more sensors as have been described herein in association with thecutting tools100,200,300. The method of determining a lateral load on a cutting tool may include operating the cutting tool and applying a lateral load on the cutting tool. Such a lateral load may be applied to one or more of the working assembly housing, the cutting element, the rotatable shaft, and the cannular shaft. Method embodiments may further include measuring load at the two or more sensors while the cutting tool is being operated. For example and without limitation,sensors190,290 of the embodiments disclosed or any other effective arrangement of sensors may be monitored and measured. The method of determining a lateral load is dependent on the direction of the applied load relative to the placement of the sensors. The present method contemplates at least two scenarios. First, if only one sensor measures a significant load, as defined herein, then the method further includes the act of comparing the measured load to a limit load to determine if an alert should be activated. Second, if more than one sensor measures a significant load, then the method further includes the act of calculating a resultant load from the loads measured and comparing the resultant load to the limit load to determine if an alert should be activated.

Various embodiments of a system wholly or its components individually may be made from any biocompatible material. For example and without limitation, biocompatible materials may include in whole or in part: non-reinforced polymers, reinforced polymers, metals, ceramics, adhesives, reinforced adhesives, and combinations of these materials. Reinforcing of polymers may be accomplished with carbon, metal, or glass or any other effective material. Examples of biocompatible polymer materials include polyamide base resins, polyethylene, Ultra High Molecular Weight (UHMW) polyethylene, low density polyethylene, polymethylmethacrylate (PMMA), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), a polymeric hydroxyethylmethacrylate (PHEMA), and polyurethane, any of which may be reinforced. Example biocompatible metals include stainless steel and other steel alloys, cobalt chrome alloys, zirconium, oxidized zirconium, tantalum, titanium, titanium alloys, titanium-nickel alloys such as Nitinol and other superelastic or shape-memory metal alloys.

Terms such as proximal, distal, near, and the like have been used relatively herein. However, such terms are not limited to specific coordinate orientations, distances, or sizes, but are used to describe relative positions referencing particular embodiments. Such terms are not generally limiting to the scope of the claims made herein. Any embodiment or feature of any section, portion, or any other component shown or particularly described in relation to various embodiments of similar sections, portions, or components herein may be interchangeably applied to any other similar embodiment or feature shown or described herein.

While embodiments of the invention have been illustrated and described in detail in the disclosure, the disclosure is to be considered as illustrative and not restrictive in character. All changes and modifications that come within the spirit of the invention are to be considered within the scope of the disclosure.

Claims (11)

What is claimed is:

1. A method of calibrating a cutting tool with integrated force sensors comprising:

coupling, by releasable locking, a drive unit with a working assembly having a proximal end, a distal end, and a longitudinal axis that passes between the proximal end and the distal end, the working assembly configured to at least in part be rotated by the drive unit, and further wherein the working assembly and drive unit are coupled by alignment of guide pins and notches;

applying a load to the working assembly, the load defining a limit load;

measuring, by way of a sensor disposed in the drive unit and adjacent to the proximal end of the working assembly, the limit load applied to the working assembly as a measured load;

registering the measured load; and

setting an alert mechanism based on the measured load such that the alert mechanism activates an alert when the sensor measures a load greater than the measured load.

2. The method ofclaim 1 wherein the limit load is applied at least in part transverse to the longitudinal axis.

3. The method according toclaim 1 wherein the limit load is applied in some component part substantially parallel with the longitudinal axis.

4. The method according toclaim 1 wherein registering the measured load includes measuring a load on only the sensor and not measuring any significant load on any other sensors.

5. The method according toclaim 1 wherein registering the measured load includes measuring loads on two or more sensors from which a resultant load is calculated.

6. The method according toclaim 1 wherein setting the alert mechanism includes setting the alert mechanism based on different measured loads to be reached for different types of working assemblies.

7. The method according toclaim 1 wherein setting the alert mechanism includes setting one or more of a visual alert, an audio alert, a tactile alert, or an alert that interrupts rotation of a part of the working assembly.

8. The method according toclaim 1 further comprising automatically setting, by the drive unit and in response to an identity of the working assembly, a different measured load at which an alert will respond.

9. The method ofclaim 8 wherein the drive unit automatically sets the different measured load by identifying a working assembly based on an arrangement of magnets in the working assembly.

10. The method ofclaim 8 wherein the drive unit automatically sets the different measured load by identifying a working assembly based on an RFID tag present in the working assembly.

11. A method of determining a lateral load on a cutting tool with one or more rotating components comprising:

coupling, by releasable locking, a drive unit to a working assembly having a proximal end, a distal end, and a longitudinal axis that passes between the proximal end and the distal end, the working assembly including a shaft configured to at least in part be rotated by the drive unit, and further wherein the drive unit and working assembly are coupled by alignment of guide pins and notches;

operating the cutting tool and applying a lateral load to the cutting tool;

while the cutting tool is being operated:

measuring, by a first sensor of two or more sensors, a first significant load, the two or more sensors disposed in the drive unit and spaced around a periphery of the proximal end of the working assembly;

measuring, by a second sensor of the two or more sensors, a second significant load;

calculating a resultant load from the first and second significant loads; and

activating an alert in response to determining the resultant load is greater than the limit load.

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